Furrow openers for use in depositing seeds, fertilizers and so forth in the soil have been of many types. There are hoe-type openers, which make a furrow by pulling a shovel or knife through the soil. There are also conventional double and single disc openers, or inclined disc openers such as that disclosed in U.S. Pat. No. 5,609,114 to Barton which all utilize a flat disc. Concave discs have also been used, which both till the soil and deposit the seed or fertilizer in the soil, covering them with soil.
With the advent of reduced tillage and increasingly no tillage, the various disc openers have gained interest because of the smaller soil disturbance caused by a disc compared to the hoe-type openers. The prior art disc openers, both flat and concave, have the axis of rotation of the disc at an angle to the direction of travel, rather than perpendicular to the direction of travel, as for instance is common with a wheel. This is required to make a furrow, since a flat disc running straight will only cut a groove in the soil the width of the disc, providing no furrow to receive seeds or fertilizer. The angle of the disc increases the width of this groove into a useable furrow. This requirement increases the power required to pull these furrow openers, and reduces the penetration of the disc in un-tilled soils.
Concave discs have been pulled at an angle to the direction of travel so that the concave side bites into the soil, with the seed being dropped on the convex side of the disc, to be covered over with soil lifted by the concave side of the next following disc. Such discs have not been suitable for no-till operations, because of the amount of soil disturbance. Placement of seed is often unsatisfactory as well with these concave disc furrow openers.
A disc-type furrow opener where the axis of rotation of the discs is perpendicular to the direction of travel would be advantageous by reducing power requirements. Such a disc that would penetrate and provide proper seed placement in un-tilled soils would be beneficial.